Esters of sulfo-benzoic and phthalic acid

ABSTRACT

WHEREIN R IS HYDROGEN OR LOWER (C1-C4)ALKYL, SUCH AS METHYL, A IS AN ALKYLENE GROUP HAVING 2 TO 10 CARBON ATOMS, AT LEAST 2 OF WHICH EXTEND IN ONE CHAIN BETWEEN THE OXYGEN ATOMS, AND X IS AN AROMATIC NUCLEUS OR AN ALKYL GROUP, SUBSTITUTED BY A SULFONIC ACID GROUP AND OPTIONALLY ONE OR MORE GROUPS SELECTED FROM SULFONIC ACID, CARBOXYLIC ACID, AND LOWER ALKYL, SUCH AS METHYL, ETHYL, PROPYL, OR BUTYL.   CH2=C(-R)-COO-A-OOC-X   THE PRESENT INVENTION IS CONCERNED WITH NOVEL MONOMERS CONTAINING SULFONIC ACID GROUPS OR SALTS THEREOF AND POLYMERS THEREOF WHICH ARE USEFUL FOR MANY PURPOSES, SUCH AS ANTISTATIC AGENTS FOR TEXTILES AND OTHER SHAPED ARTICLES FORMED OF HYDROPHILIC MATERIALS. THEY ARE USEFUL FOR MAKING COPOLYMERS THAT ARE PARTICULARLY VALUABLE IN COATING COMPOSITIONS, ESPECIALLY IN THE FORM OF AQUEOUS LATICES OR ORGANIC SOLVENT SOLUTIONS THEREOF. EXAMPLES OF THE MONOMERS ARE OF THE FORMULA

United States Patent 3,770,801 ESTERS 0F SULFO-BENZOIC AND PHTHALIC ACIDWilliam D. Emmons, Huntingdon Valley, and Graham Swift, Ambler, Pa.,assignors to Rohm and Haas Company, Philadelphia, Pa.

No Drawing. Filed Apr. 16, 1971, Ser. No. 134,905 Int. Cl. C07c 143/52US. Cl. 260-470 7 Claims ABSTRACT OF THE DISCLOSURE The presentinvention is concerned with novel monomers containing sulfonic acidgroups or salts thereof and polymers thereof which are useful for manypurposes, such as antistatic agents for textiles and other shapedarticles formed of hydrophilic materials. They are useful for makingcopolymers that are particularly valuable in coating compositions,especially in the form of aqueous latices or organic solvent solutionsthereof. Examples of the monomers are of the formula R is hydrogen orlower (C -C )alkyl, such as methyl,

A is an alkylene group having 2 to 10 carbon atoms, at

least 2 of which extend in one chain between the oxygen atoms, and

X is an aromatic nucleus or an alkyl group, substituted by a sulfonicacid group and optionally one or more groups selected from sulfonicacid, carboxylic acid, and lower alkyl, such as methyl, ethyl, propyl,or butyl.

The new monomers of the present invention are those of the GeneralFormula I as follows:

wherein R is hydrogen or lower (C -C )alkyl, preferably hydrogen ormethyl,

A is an alkylene group having 2 to 10 carbon atoms, at least 2 of whichextend in a chain between the adjoined oxygen atoms, and

X is either (1) an aromatic nucleus, such as a benzene or naphthalenering, substituted by a sulfonic acid group and optionally one or moresulfonic acid or carboxylic acid groups, or (2) an alkyl group,substituted or unsubstituted, of the formula a (II) wherein one of R andR is a sulfonic acid group and the other is H,

R is H or a (C -C alkyl group,

R is H, COOH, or a (C -C )alkyl group, and

R is H or a (C C )alkyl group, with the proviso that only one of R R andR is alkyl except that both R and R may be alkyl provided, in that case,R and R are both H.

Preferred monomers are those which contain both a carboxyl group and asulfonic acid group. In these monomers the group X of Formula II aboveis defined as follows 3,770,801 Patented Nov. 6, 1973 "ice one of R andR is a sulfonic acid group and the other is H,

R is H or a (C -C )alkyl group, and

R is H or a (C -C )alkyl group.

Preferably, when one of R and R is an alkyl group, the other is H.

While the description so far recites that the monomers contain asulfonic acid group and optionally a carboxylic acid group, it is to beunderstood that they may contain more than one sulfonic acid group andmore than one carboxylic acid group and also that the salts of suchmonomers are also part of the present invention. The salts of themonomers may be formed with any basic material, organic or inorganic,such as an alkali metal or alkaline earth metal hydroxide, ammoniumhydroxide, primary, secondary or tertiary amine, whether volatile ornot, such as methylamine, dimethylamine, trimethylamine, thecorresponding ethyl, propyl, isopropyl, n-butyl, isobutyl, andtertiary-butyl amines, monoethanolamine, diethanolamine, andtriethanolamine, and quaternary ammonium bases, such asbenzyltrimethylammonium hydroxide, and so on.

In general, the monomers of the present invention may be obtained invarious ways but a preferred method is to react (1) a neutral alkylester of an a,B-monoethylenically unsaturated acid, such as acrylicacid, methacrylic acid, and itaconic acid in which the alkyl group orone of the alkyl groups contains 2 to 10 carbon atoms and a hydroxygroup spaced by at least 2 carbon atoms from the ester linkage with (2)an anhydride of an organic carbo-xylic acid containing a sulfonic acidgroup.

The reactant (1) has the general Formula IV as follows:

wherein the symbols are the same as stated in the definition of FormulaI.

Examples of the neutral ester 1) include:

fi-hydroxyethyl acrylate and methacrylate methyl p-hydroxyethylitaconate 2-hydroxypropyl acrylate and methacrylate 3-hydroxypropylacrylate and methacrylate 2-hydroxy-l-methyl-ethyl acrylate andmethacrylate 2-hydroxy-butyl-acrylate and methacrylate3-hydroxy-butyl-acrylate and methacrylate 4-hydroxy-butyl-acrylate andmethacrylate 2-hydroxy-2-methyl-butyl acrylate and methacrylate2-hydroxyethoxyethyl acrylate and methacrylate S-hydroxypentyl-acrylateand methacrylate 6-hydroxyhexyl-acrylate and methacrylate7-hydroxyheptyl-acrylate and methacrylate 4-hydroxy-2-ethyl-butylacrylate and methacrylate 6-hydroxy-2-ethyl-hexyl acrylate andmethacrylate 9-hydroxynonyl acrylate and methacrylate 10-hydroxydecylacrylate and methacrylate The anhydrides used in the preparation of thesulfoester monomer are the anhydrides of the 1,2-diacid compoundsdefined by the formula no-i z-oc v wherein X is either (1) an aromaticnucleus, such as a benzene or naphthalene ring, substituted in the2-position by a sulfonic acid group or a carboxylic acid group andoptionally in one or more additional positions by one or more sulfonicacid or carboxylic acid groups, or (2) an alkyl group, substituted orunsubstituted, of the formula wherein R, R R R and R are as definedhereinabove.

Examples of the anhydrides (2) include:

o-sulfobenzoic anhydride 4-methyl sulfobenzoic anhydride 4-sulfophthalicanhydride 3,5-disulfophthalic anhydride 4-sulfo-l,9-naphthalic anhydridesulfosuccinic anhydride methyl sulfosuccinic anhydride ethylsulfosuccinic anhydride butyl-sulfosuccinic anhydride sulfopropionicanhydride, i.e., 1,2-xathiolane-5-one-2,2-

dioxide of the formula:

4-methyl-l ,2-oxathiolane--one-2,2-dioxide4-isobutyl-1,2-oxathiolane-5-one-2,2-dioxide4-ethyl-1,2-oxathiolane-5-one-2,2-dioxide 3-methyl- 1,2-oxathiolane-5-one-2,2-dioxide3,4-dimethyl-l,2-oxathiolane-5-one-2,2-dioxide The aromatic anhydridesmentioned hereinabove are known compounds. Many of the aliphaticanhydrides listed above are also known. The alkyl-succim'c anhydridesare obtained by the reaction of an a-olefin such as ethylene, propylene,butylene or isobutylene with maleic anhydride. The reaction may becarried out in the presence of an inert solvent such as benzene, andxylene, but a separate solvent is unnecessary if the temperature is highenough to melt the maleic anhydride. Generally, the reaction is effectedat a pressure of 25-50 atmospheres which may decrease during thereaction and at a temperature of 150-250 C. for a period of 8-24 hours.The relative proportions between the reactants may vary widely so thateither one may be in excess, an excess of the gas being preferredbecause of its relative inexpensiveness, but stoichiometric proportionsmay be used.

The resulting alkyl-succinic acid may then be sulfonated with liquidsulfur trioxide at atmospheric pressure or higher and at roomtemperature up to 110 C., refluxing if necessary, for a period of aboutl-4 hours. The ratio of sulfur trioxide and alkyl-succinic acid employedfor the reaction may be stoichiometric or an excess of sulfur trioxidemay be used in which case it serves as a solvent.

The oxathiolanes may be produced by the addition of sodium bisulfite(NaHSO to a sodium salt of an appropriate nip-unsaturated acid. Thereaction may be carried out in an aqueous medium at room temperature for2-12 hours. Generally, it is preferred to employ approximatelystoichiometric amounts. The reaction is carried out until the bisulfiteion disappears as indicated by permaganate titration. At the conclusionof the reaction the product is concentrated and converted into the freeacid form by ion exchange with a cation exchanger in acid form. The ionexchange resin is filtered off and then the product is stripped anddried. The closure to form the ring is effected in thionyl chloride byheating at temperatures of 6080 C. and preferably at reflux for twohours or so. A volatile hydrocarbon solvent, such as ligroin orpetroleum ether, is added to precipitate the oxathiolane which then canbe separated by filtration or decantation and dried. Unsaturated acidsmay be used to form the various oxathiolanes listed above and othersinclude:

acrylic acid methacrylic acid crotonic acid e-rnethylene-bntanoic acida-methylene-pentanoic acid a-methylene-hexanoic acid Z-pentenoic acidZ-hexenoic acid 2-heptenoic acid a-methyl-crotonic acidot-ethyl-crotonic acid a-propyl-crotonic acid a-butyl-crotonic acidu-isobutyl-crotonic acid wmethyl-Z-pentenOic acid a-ethyl-2-pentenoicacid a-isopropyl-2-pentenoic acid a-methyl-2-hexenoic acidu-ethyl-2-hexenoic acid a-propyl-2-hexenoic acid u-isobutyl-2-hexenoicacid u-isopropyl-2-heptenoic acid 2-metl1ylene-4-methyl-pentauoic acid2-ethylidene-4-methyl-pentanoic acid 2-propylidene-4-methyl-pentanoicacid 2-butylidene-4-methyl-pentanoic acid 2-methylene-hexanoic acidZ-butyIidene-hexanoic acid The reaction between the unsaturatedhydroxyester (1) and the sulfocarboxylic acid anhydride (2) may be carried out under suitable agitation or stirring with a solvent inert tothe reactive agents or it may be carried out with out a separatesolvent. Examples of materials that may be used as solvents includeesters, such as ethyl acetate, methyl methacrylate, and butyl acetate,hydrocarbons, such as benzene, toluene, xylene, and ethylbenzene,dimethyl sulfoxide, dioxane, acetonitrile, and so on. The temperaturemay be from about 0 C. to 130 C. but is preferably in a range from about20 C. to about 110 C.

The mole ratio of the unsaturated hydroxyester to the sulfocarboxylicanhydride may vary widely. For most practical operations, a ratio isused in the range of 1.5 :1 to 1:2 (hydroxyester to anhydride) and thepreferred range is from about 1:1 to about 121.25.

If it is desired to avoid contamination of the monomeric product with apolymer thereof, a polymerization inhibitor may be used, such as in anamount in the range of about 100 parts per million (p.p.m.) to about6000 p.p.m., preferebaly 1000 to 3000 p.p.m., based on the weight of theester. Examples of inhibitors include hydroquinone and the monoanddi-methyl ethers thereof. The time required for the reaction may be fromabout a half hour to eight hours or more to reach equilibriumconditions. Volatile materials may be removed from the product obtainedby vacuum distillation or by extraction with solvents and subsequentdistillation of the solvent from the extract.

The sulfonic acid monomer obtained by the reaction is generally obtainedin a yield of -95% based on the anhydride used assuming approximatelyequal molar amounts of the hydroxy alkyl-acrylate and anhydride are usedin the reaction. The monomer of Formula I which results from thereaction and is present in acid form in the reaction medium may bedirectly polymerized with whatever residual content of hydroxyalkylacrylate or methacrylate monomer is unused in the reaction. However, itmay be desirable to isolate either a salt of the sulfonic acid monomeror such monomer in acid form for the purpose of producing homopolymersof such a monomer either in acid or salt form. The sulfo monomer may beisolated from the reaction product by precipitating it with sodiummethoxide which forms a salt of the sulfonic acid monomer which isinsoluble in whatever organic solvent is used in the preparation of themonomer. Such solvents may be esters, such as ethyl acetate, orhydrocarbons, such as toluene or xylene. After precipitation of the saltof the sulfonic acid monomer, it may be filtered and washed with asolvent such as an ester or an aromatic solvent, ethyl acetate, tolueneor xylene being representative of suitable solvents for this purpose. Ifit is desired to produce a homopolymer of the salt of the monomer thusobtained it may be mixed with a suitable initiator in an aqueous medium.Initiators, such as sodium hydrosulfite, also tertiary-butylhydroperoxide, hydrogen peroxide or other water-soluble initiator may beused.

If a homopolymer of the sulfonic acid containing monomer is desired theprecipitated salt of of the monomer which has been filtered and Washedas mentioned just above may be suspended in a suitable solvent such asethyl acetate or toluene and agitated for a period of time with a strongacid ion exchange resin. For example, the suspension of the monomer saltin the organic solvent may be agitated with beads of a sulfonatedstyrene/divinyl benzene ion exchange resin for a period of several hoursat room temperature. The ion exchange resin is initially in the acidform and exchanges the metal ion with the monomer salt and therebyliberates the free acid form of the sulfonic acid containing monomer. Asa result of the ion exchange action the monomer is converted to acidform which is soluble in the organic solvent used for suspending thesalt form and the ion exchange resin. At that point it is merelynecessary to filter off the ion exchange resin.

The acid form of the monomer thereby obtained can then be polymerized,such as in the solution in which it is obtained, by the mere addition ofsuitable free radical initiators such as azodiisobutyronitrile, diethyldiazodiisobutyrate, benzoyl peroxide or other initiator soluble in theorganic solvent.

The acid form of this homopolymer or copolymers obtained from thesulfonic acid monomers of the present invention can be convertedessentially entirely or partially to the salt form simply by adding abase, such as an alkali metal hydroxide, alkyline earth metal hydroxide,ammonium hydroxide, or an amine or quaternary ammonium hydroxide. Thesalt form of the homopolymers or copolymers can also be partially orcompletely converted to the acid form by leaching the polymers with astrong acid.

The reaction between the unsaturated hydroxyester (l) and thesulfocarboxylic acid anhydride may be carried out under suitableagitation or stirring with a solvent inert to the reactive agents or itmay be carried out without a separate solvent. Examples of materialsthat may be used as solvents include esters, such as ethyl acetate,methyl methacrylate, and butyl acetate, hydrocarbons, such as benzene,toluene, xylene, and dimethyl sulfoxide, dioxane, acetonitrile, and soon. The temperature may be from about 0 C. to 130 C. but is preferablyin a range from about 20 C. to about 110 C.

The mole ratio of the unsaturated hydroxyester to the sulfocarboxylicanhydride may vary widely. For most practical operations, a ratio isused in the range of 1.5:1 to 1:2 (hydroxyester to anhydride) and thepreferred range is from about 1:1 to about 121.25.

If it is desired to avoid contamination of the monomeric product with apolymer thereof, a polymerization inhibitor may be used, such as in anamount in the range of about 100 parts per million (ppm) to about 6000p.p.m., preferably 1000 to 3000 p.p.m., based on the weight of theester. Examples of inhibitors include hydroquinone and the monoanddi-methyl ethers thereof. The time required for the reaction may be fromabout a half hour to eight hours or more to reach equilibriumconditions. Volatile materials may be removed from the product obtainedby vacuum distillation or by extraction with solvents and subsequentdistillation of the solvent from the extract.

The monomeric products obtained, whether or not isolated from thereaction medium are polymerizable to produce homopolymers and/ orcopolymers, as desired, by bulk, emulsion, solution, and suspensionprocedures. In general, the monomers of Formula I are Water-soluableliquids that form water-soluble salts, generally solid and crystalline,with basic material, such as the various bases mentioned hereinabove.

There are many known polymerizable, a,B-ethylenically unsaturatedcompounds that can be polymerized while dispersed in aqueous media bymeans already known per se to produce aqueous colloidal dispersions ofsubstantially water-insoluble solid polymer products. These can beadvantageously polymerized in aqueous dispersions that comprise one ofthe sulfoester monomers of Formula I of this invention.

Among such other known polymerizable ethylenically unsaturated compoundsare the alkenyl-aromatic compounds, i.e., styrene and 0-, m-, andp-vinylstyrene, the derivatives of a,B-ethylenically unsaturated acidssuch as the esters, amides, and nitriles of acrylic acid, methacrylicacid, itaconic acid, and maleic acid, unsaturated alcohol esters,unsaturated ketones, unsaturated ethers, and other compounds containingone or more ethylenic linkages, especially those having a singleunsaturated group of the formula H C=C capable of additionpolymerization. Specific examples of such ethylenically unsaturatedcompounds are styrene, a-methylstyrene, ar-methylstyrene,ar-ethylstyrene, a,ar-dimethylstyrene, ar-ar-dimethylstyrene,vinylnaphthalene, hydroxystyrene, methoxystyrene, cyanostyrene,acetylstyrene, monochlorostyrene, dichlorostyrene and otherhalostyrenes, methyl methacrylate, ethyl acrylate, butyl acrylate, butylmethacrylate, hexyl acrylate, lauryl methacrylate, phenyl acrylate,acrylonitrile, methacrylonitrile, acrylanilide, acrylamide, N-methylolacrylamide, ethyl u-chloroacrylate, ethyl maleate, polyglycolmaleate, vinyl acetate, vinyl propionate, vinyl butyrate, vinylbenzoate, vinyl chloride, vinyl bromide, vinylidene chloride, vinylidenebromide, vinyl methyl ketone, isopropenyl ketone, vinyl ethyl ether, anddienes which generally act as though they have only one point ofunsaturation during normal polymerization, such as 1,3- butadiene,isoprene, and the like.

The monomers of Formula I and their water-soluble salts ma behomopolymerized in bulk or in an aqueous solution thereof using asuitable polymerization catalyst or initiator or an initiator system,such as a redox system. The catalyst or initiator may simply beradiation, especially ultra-violet light, or it may be a free radicaltype of initiator, miscible with the monomer or soluble in the aqueousmedium. Examples include hydrogen peroxide, ammonium or an alkali metal(e.g. sodium or potassium) persulfate, t-butyl hydroperoxide, cumenehydroperoxide or azo-bisisobutyronitrile. Such initiators may be used inthe customary amounts of about 0.1 to 3% by Weight based on totalmonomer weight. In redox systems, a free radical initiator, such as ofthe type mentioned is used with a reducing agent, such as sodiumhydrosulfite, potassium metabisulfite, or ascorbic acid, in comparableamounts, e.g. 0.1 to 3% based on monomer weight. Any suitable pH may bemaintained such as in the range from 3 to 10, an acid, base, and/orbuffering agent or agents being included as desired.

Homopolymers and copolymers can also be produced in any other solventmedium, such as an ester, e.g. ethyl acetate, a ketone, e.g., acetone ormethyl isobutyl ketone, an ether, e.g. dioxane, and the dimethyl etherof diethylene glycol, or mixtures containing two or more such solventsor containing water and one or more of the organic solvents justmentioned. Alcohols are unsuitable for use as the solvent mediumwhenever complex ester product mixtures are to be avoided. An initiatoror initiator system that is soluble in the medium may be used, such asany of those mentioned above for use in the aqueous systems.

Copolymers of one or more other monomers, such as those previouslymentioned, with a monomer of Formula I can be produced elficiently in anaqueous medium, with or without the use of an emulsifying agent to aidin the dispersion of any water-insoluble monomer. When an emulsifier isused, it may be used in conventional amount in the range of 0.05 to 6%or more based on the weight of water-insoluble monomer used in thepolymerization process. The water-soluble initiator or initiator systemsmentioned above may be used in the amounts stated. Generally, thepolymers produced have high molecular weight, such as from about onemillion to ten millions or more. However, a chain transfer agent, suchas bromotrichloroethane, methylene chloride, a (C C )alltyl mercaptan,e.g. dodecyl mercaptan, or a hydroxyalkyl mercaptan, e.g. B-hydroxyethylmercaptan, may be used to obtain polymers of lower molecular weights,such as from about 10,000 to any point below that which the system inuse normally produces without such an agent, the more of the agent used,the lower the molecular weight for any particular chain transfer agent.The amount of such an agent used may be from about 0.05% to 10% or morebased on the total monomer weight.

A suspension polymerization technique of normal type employing acolloid, such as polyacrylic acid or poly (e-vinyl-pyrrolidinone), maybe used to form copolymers containing a large proportion of at least onemonomer of Formula I cross-linked by about to 5 to 50% (preferably 15 to35%) by Weight of a diethylenically unsaturated copolymerizable monomersuch as divinyl benzene, ethylene glycol dimethacrylate, or diallylphthalate. Such polymers are obtained in the form of beads or granuleswhich are useful as cation-exchange resins.

The monomers of Formula I as well as the homopolymers of a monomer ofFormula I herein and copolymers formed largely (at least 55% by weight)of one or more monomers of Formula I and containing to 45% by weight ofother monomers of the types mentioned hereinabove are useful assurfactants, such as wetting agents, as antistatic agents for textilesand other articles formed of hydrophobic materials such as nylon,cellulose esters, and polyesters and as softening agents for textiles,such as cotton and rayon. They are also useful as conductivity aids inpaper, such as that used in electrostatic reproduction. They are alsouseful to stabilize aqueous polymer dispersions and water-base paintsagainst coagulation as a result of freezing and subsequent thawing.They, and especially the polymers, are useful as flocculating agents. Toserve these purposes, the amount of the monomer or polymer needed isquite small relative to the magnitude of the system to which or in whichthey are applied.

When a relatively small amount of a monomer of Formula I is incorporatedas a polymerized component in water-insoluble polymers used in thecoatings industry, the copolymers that are obtained show remarkableimprovements in adhesion to various substrates, and especially those of,or carrying a deposit of, a plastic or resinous material.

The polymers contemplated here are the addition polymers of at least onemonoethylenically unsaturated monomer having a group of the formula HC:C including a vinyl ester of a (C C )alkanoic acid, e.g. vinylacetate, vinyl versatate, and vinyl dodecanoate; a (C -C alkyl ester ofacrylic acid or methacrylic acid, such as methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butylmethacrylate, 2- ethylhexyl acrylate or methacrylate; a vinylaromatichydrocarbon, such as styrene and vinyltoluene; acrylonitrile, acrylamideand so forth.

Thus the copolymers containing from as little as 0.1% by weight, basedon copolymer weight, up to 2% or 5% by weight of a monomer Of Formula Iare exceptionally useful for improving the adhesion of coatings ofcompositions comprising such copolymers when applied to substrates ofmetal, glass, or plastic carrying a deposit of a Vic-epoxy resin primer,an aminoplast resin primer, or primers formed of mixtures of suchresin-forming substances, all of which are of commercial types commonlyavailable on the market.

Copolymers of monoethylenically unsaturated compounds containing smallamounts of a monomer of Formula I such as from about 0.2% to 5% or evenup to 10% are useful to impart antistatic properties to textiles andother materials formed of hydrophobic materials, such as nylon,cellulose esters including cellulose acetate and cellulose acetatebutyrate, and polymers such as the condensates of ethylene glycol withterephthalic acid. Preferably, such copolymers are prepared by emulsionpolymerization processes so that a latex or aqueous dispersion of thepolymer is produced containing anywhere from 20 to 60% by weight of thepolymer dispersed therein. In applying the dispersion to the fabric orother materials the dispersion may be diluted to about 15 to 30% solidsand applied by spraying, use of a textile pad, or brushing as is mostsuitable for application to the particular substrate involved. Effectiveantistatic properties are obtained by the application of an amount fromabout 0.1 to 1% by weight of the polymer based on the weight of fibersin the case of the textile material whereas effective antistaticproperty is obtained by the application of such a polymer on a solidarticle such as a molded plastic article when the polymer is depositedin the form of a thin film of about 1-10 microns thickness.

In the preferred monomers there is a carboxylic acid group as well asthe sulfonic acid group or groups. There is an advantage in havingcarboxyl groups in addition to the sulfonic acid groups. The presence ofthe carboxyl group is particularly important in aqueous polymerdispersions made from the polymers containing small amounts, such as 0.2to 5% by weight, of a monomer of Formula I in that such dispersions andcompositions made therefrom, such as water base paints, can readily bethickened by the addition of a basic material such as sodium hydroxide,ammonium hydroxide or an amine. This amenability to thickening byadjustment of the pH of the system when such a basic material is addedprovides an eificient way of controlling the viscosity and consistencyof the products to adapt them for any particular manner of applicationfor use as in brushing, spraying or the like.

Another remarkable property that is clearly enhanced by the presence ofcarboxyl groups in the polymers is the dispersing action of suchpolymers for fillers, pigments, delustrants and other inert materials.The dispersancy improvement occurs not only in aqueous dispersions ofthe polymers containing the monomers of Formula I when it containscarboxyl groups but also is found to occur in inorganic solvent systemscontaining such polymer dissolved therein or dispersed therein in theform of a nonaqueous dispersion. While these adavntages i.e.,amenability to thickening and improvement of dispersing action can beobtained when the polymer is made from a monomer of Formula I lackingcarboxylic acid groups by the inclusion of separate carboxylic acidmonomers such as acrylic acid, methacrylic acid and itaconic acid insmall amounts such as from 0.2 to 5% by weight in the polymer,nevertheless it has generally been found that the inclusion of thecarboxylic acid groups in the sulfoester monomer of Formula I is morepractical and efiicient as well as somewhat more economical. Thus thepreferred monomers that incorporate both sulfonic acid and carboxylicacid groups (in free acid or salt form) provide outstanding quantitiesin compositions such as water base paints made therefrom.

While the polymers of the invention hereinabove described are produceddirectly by polymerization of a monomer of Formula I, another avenue toproduce polymers of the present invention is to polymerize ahydroxylcontaining ester monomer of Formula IV and after production ofthe polymer reacting it with an anhydride of a compound of Formula V.The polymerization of the hydroxyl-containing compound is well known inthe art and the reaction with the anhydride can be carried out underessentially the same conditions as are specified hereinabove in thedescription of the procedure for reacting such an anhydride with such ahydroxy ester in making the monomers of Formula I.

To assist those skilled in the art to practice the present invention,the following modes of operation are suggested by way of illustration,parts and percentages being by weight and the temperature in C. unlessotherwise specifically noted.

(A) PREPARATION OF 4-SULFOPHTHALIC ANHYDRIDE Phthalic anhydride (148grams) and chlorosulfonic acid (116.5 grams) are mixed in a reactionflask fitted with a condenser, stirrer and thermometer. The reactiontemperature is raised to 225 C. over a period of about 14 hours. After afurther 2 hours at this temperature, g.l.c. analysis indicates that thereaction mixture still contains by weight of phthalic anhydride. Atabout 23 hours total reaction time phthalic anhydride is no longerdetectable. The resulting product is cooled to 160 C. and stripped formin. at 20 mm. Hg to remove residual hydrogen chloride. Cooling to roomtemperature affords a viscous red liquid having infrared (I.R.) spectraldata and equivalent weight (76) consistent with 4- sulfophthalicanhydride.

(B) PREPARATION OF SULFONIC ACID MONOMERS (1) Preparation ofmethacryloxyisopropyl acid sulfophthalate (a) A mixture of 239 g.4-sulfophthalic anhydride (1.05 M), 151 g. 2-hydroxypropyl methacrylate(1.05 M), 260 g. methyl methacrylate (2.6 M) as solvent, and themonomethyl ether of hydroquinone (0.25 g.) is charged to a reactorfitted with a condenser, thermometer, stirrer, and an air-sparge tube.The stirrer is operated continuously and dry air is passed through thetube at a rate of about 300 ml./min. After 2 hours at C. the product iscooled to room temperature. Analysis indicates that the equilibriummixture contains about 55 by weight methacryloxyisopropyl acidsulfophthalate.

The mixture obtained can be used directly for polymerization but it maybe desirable to purify the monomer as follows: Add sodium methoxide insufficient quantity to precipitate the sodium salt of the sulfonic acidmonomer. Then filter and Wash with ethyl acrylate or xylene. Thismonomer salt can be homopolymerized by adding it to water and thenadding a polymerization initiator. The example, add 100 g. of themonomer salt to 180 g. of water. Then add 0.9 g. sodium persulfate. Themixture is maintained at 50 C. to.60 C. until the reaction subsides asevidenced by reduction in temperature.

(b) The homopolymer salt thus obtained in part (a) is useful as apolymeric electrolyte. For example, it serves as a suspending agent in asuspension polymerization as follows: A 1% solution of this polymer saltin a liter of water is heated to 50 C. with agitation. Then, whilecontinuing the stirring, a mixture of 400 g. of styrene, 100 g. ofdivinylbenzene and 4 g. of benzoyl peroxide is added over a period of 6hours while maintaining the temperature so that it does not exceed 85 C.The styrene/divinylbenzene copolymer precipitates as small beads which,on sulfonation in conventional manner, are converted into a strong acidion-exchange resin.

(c) The filtered and washed monomer salt obtained in part (a) (50 g.) isstirred in 200 g. ethylacetate and 75 g. of a granular sulfonatedstyrene/divinylbenzene ion-exchange resin in acid form is stirred in.The resulting mixture is stirred continuously for a period of four hoursat room temperature. The monomer as it is converted to acid formdissolves in the solvent. The resulting slurry is then filtered yieldinga filtrate containing approximately 23% of the methacryloxyisopropylacid sulfophthalate. About 1.5 g. of lauroyl peroxide is added to thesolution and the temperature then rises to about C. After an hour ofpolymerization, the temperature falls. Cotton and viscose yarns arepassed through the polymer solution after dilution to about 5%concentration with additional ethyl acetate. The yarns are then heatedto evaporate the solvent in a suitable evacuation chamber. The yarns arethereby sized for protection during textile operations, such as weavingor knitting. After the latter operations, the size is removed by passageof the fabric through an alkaline bath.

(d) In a similar fashion to that described in part (a)methacryloxyisopropyl acid sulfophthalate is obtained as a 55% solutionin ethyl acetate. It is converted to the sodium salt in the same day asdescribed in part (a) hereof.

(2) Preparation of methacryloxyisopropyl sulfobenzoate (a) 54.7 g.2-hydroxypropyl methacrylate (0.38 M), g. o-sulfobenzoic anhydride (0.38 M) and the monomethyl ether of hydroquinone (0.1 g.) are dissolvedin toluene (35 g.) and heated to 110 C. The mixture is agitated andsparged with dry air as in (1) above. After 2 hours, the reactionmixture is cooled and analysis shows that methacryloxyisopropylsulfobenzoate is obtained in approximately yield based on o-sulfobenzoicanhydride charged.

(b) To the resulting solution of methacryloxyisopropylsulfobenzoate intoluene there is added sodium methoxide to effect precipitation of thesalt of the monomer. The precipitated salt is filtered and rinsed withadditional toluene. The salt is polymerized in the same way as thefiltered and washed monomer salt obtained in 1) (a) above. The resultingpolymer is used as a suspending agent in a suspension polymerization inthe same way as is described in procedure (1) (b) above.

(c) The filtered salt of the methacryloxyisopropyl sulfobenzoate isconverted to the acid form in the same way as described in (l)(c) above.The resulting monomeric acid is polymerized in the same day as describedin part (l)(c) and is applied for the sizing of warp yarns in the sameway as therein described. As in the previous in! stance, the size isreadily removable in an aqueous alkaline solution.

(3) Preparation of methacryloxyisopropyl acid sulfosuccinate Into areaction flask fitted with a thermometer, stirrer, condenser, and anair-bleed tube, there is charged 21.8 g. potassium sulfosuccinicanhydride (0.1 M), 14.4 g. 2- hydroxypropyl methacrylate (0.1 M),dimethyl sulfoxide (34 g.) and the monomethyl ether of hydroquinone(0.02 g.). The reactants are agitated and sparged with air as in (1) andthey are heated to C. for 6 hours and then cooled to room temperature. Acalculated quantity of a sulfonated styrene/divinyl benzene ion-exchangeresin is added and stirring is continued at 25 C. for 16 hours. Afterfiltering to remove the ion-exchange resin, a 40% by weight solution ofmethacryloxyisopropyl acid sulfosuccinate in dimethyl sulfoxide isobtained.

The resulting monomer is polymerized by adding benzoyl peroxide (1 gramthereof per 100 grams of monomer) to the solution thereof andmaintaining it at a temperature of about 60 C. for several hours. Cottonand rayon yarns are sized in the resulting solution of polymeric acid,the solvent being evaporated after application to the yarns. The sizedyarns are fabricated into textile fabrics and thereafter the fabrics areimmersed in an 1 1 aqueous alkaline medium such as 1% sodium hydroxidesolution to remove the size from the fabric.

(4) Preparation of methacryloxyethyl sulfobenzoate Hydroxyethylmethacrylate (65 g.) o-sulfobenzoic anhydride (92 g.), the monomethylether of hydroquinone (0.2 g.) and toluene (157 g.) are stirred, spargedwith dry air, and heated at 110 C. for 2 hours and then cooled to roomtemperature. Analysis indicates an approximately 74% conversion ofanhydride into methacryloxyethyl sulfobenzoate.

The resulting monomer may be converted, by salting out, into the saltwhich can be polymerized in the fashion described hereinabove or themonomeric salt may be converted back to the acid form of the monomer byuse of ion exchange resins as described hereinabove and the resultingsolution of the acid form of the monomer may be polymerized to form apolymer which is a suitable size for textile yarns that is readilyremovable after fabrication of the yarns into a textile fabric by meansof an alkaline medium.

(5) Preparation of methacryloxyisopropyl sulfopropionate To a reactionvessel fitted with an air-bleed tube, thermorneter, stirrer, andcondenser there are charged sulfo propionic anhydride (29.1 g.),2-hydroxypropyl methacrylate (29.1 g.), the monomethyl ether ofhydroquinone (0.1 g.) and toluene (60 g.). The mixture is stirred,sparged with dry air as in (1) above and heated. After 0.5 hour at 60 C.a solution containing 29% by Weight of methacryloxyisopropylsulfopropionate is obtained.

(6) Preparation of methacryloxyisopropyl acid sulfophthalate (a) Amixture of 228 parts of 4-sulfophthalic anhydride (1.0 M), 144 parts ofhydroxypropyl methacrylate (1.0 M), 260 parts of methyl methacrylate(2.6 M) as solvent, and the monomethyl ether of hydroquinone (0.25 part)is charged to a reactor fitted with a condenser, thermometer, stirrerand air-sparge tube. A slow stream of dry air is passed through thesolution while maintaining a temperature of 60 C. by the application ofexternal heating. After 2 hours the product is cooled to roomtemperature and analyzed. The product contains approximately 53% byweight of methacryloxyisopropyl acid sulfophthate.

(b) Substituting 129.8 parts of hydroxypropyl methacrylate for the 144parts used in (6) (a) above, yields a product containing approximately50% Wt. methacryloxyisopropyl acid sulfophthalate.

(7) Preparation of methacryloxyethyl acid sulfo-methyI-succinate (a) Amixture of 194 g. of sulfo-methyl-succinic anhydride, 130 g. ofB-hydroxyethyl methacrylate, 280 g. of methyl methacrylate and 0.3 g. ofthe monomethyl ether of hydroquinone is charged to a reaction vessel.The mixture is continuously stirred and dry air is passed through thesolution at a rate of 200 ml./min. The mixture is heated 2 hours at 60C. and then cooled to room temperature. The product may also be namedthe mono(B methacryloxyethyl) ester of sulfo-methyl-succinic acid.

(b) Preparation of sulfo-methyl-succinic anhydride 114 g. ofmethyl-succinic anhydride and 80 g. of liquid sulfur trioxide arestirred and heated to 110 C. in an apparatus fitted with a condenseradequate to contain the low boiling sulfur trioxide. After 1 hour, theproduct is cooled to C. and has an equivalent weight of about 65. It isstored as a solution in methyl methacrylate.

(c) The methacryloxyethyl acid methyl-sulfosuccinate obtained in part(a) hereof can be used directly for polymerization or it may beprecipitated from solution (8) Preparation of methacryloxyethyl acidn-butyl-sulfo-succinate (a) This product is obtained from B-hydroxyethylmethacrylate and n-butyl-sulfo-succinic acid anhydride by the procedureof (7)(a) using corresponding molar amounts of the reactants. Theanhydride is obtained as follows:

(b) 30 g. of maleic anhydride and 40 g. of butene-l are dissolved in 40g. benzene in an autoclave. After 8 hours heating at 250 C. a pressuredrop from 40 to 2 atmospheres is noted and the reaction is terminated.The brown solution obtained is vacuum-distilled to yield 40 g. ofbutenylsuccinic anhydride, boiling range 144-147 C. at 4 mm. Hgpressure, characterized as the free acid M.P. 114 C., literature 114-115C.

40 g. of the butenylsuccinic acid is hydrogenated in methanol over aplatinum catalyst to yield n-butylsuccinic acid, M.P. 8283 C. Ringclosure to n-butylsuccinic anhydride is achieved by mixing it with 100g. of acetic anhydride and distilling acetic acid as it is formed. Theresulting crude product is directly sulfonated by the procedure of (7)(b) using corresponding molar amounts of the n-butyl-succinic anhydrideand S0 (9) Preparation of methacryloxyisopropyl sulfo-isobutyrate (a)150 g. of 4-methyl 1,2 oxathiolane-5-one-2,2- dioxide prepared asdescribed in part (b) hereof, 144 g. of ,B-hydroxypropyl methacrylate,0.2 g. of the monomethyl ether of hydroquinone and 200 g. of toluene areheated at 60 C. with stirring and air sparging with 200 ml./ min. of dryair for 1 hr. The cooled mixture contains a yield ofmethacryloxyisopropyl sulfo-isobutyrate.

(b) Preparation of 4-methyl-1,2-oxathiolane-5-one-2,2- dioxide: 88 g. ofisobutyric acid dissolved in g. of sulfuryl chloride is heated at 80 C.and irradiation with a 300 watt tungsten lamp for 2 hours. Addition ofligroin precipitates an oil which has a boiling range -140 at 4 mm. andis identified as 4-methyl-1,2-oxathiolane-5-one- 2,2-dioxide by itsequivalent weight, 75.

(10) Preparation of methacryloxyisopropyl S-sulfo-hexanoate (a) 178 g.of 3 prop-yl 1,2 oxathiolane 5 one- 2,2-dioxide is reacted with 144 g.of fi-hydroxypropyl methacrylate in toluene as described in procedure(7) (a) above.

(b) Preparation of 3-n-propyl 1,2 oxathiolane-S-one- 2,2-dioxide: 114 g.of Z-hexenoic acid is neutralized with aqueous sodium hydroxide andreacted with 204 g. of a 50% wt. aqueous solution of sodium bisulfite at25 C. Complete addition of bisulfite to the double bond requires severalhours. The product is concentrated to approximately 50% wt. solids andthen treated with a strong acid ion exchange resin to obtain an aqueoussolution of 3-sulfohexanoic acid. This is dried by vacuum stripping andconverted into 3-propyl-1,2-oxathiolane-5- one-2,2-dioxide withrefluxing thionyl chloride at 80 C. for 3 hours. Equivalent weight is93.

( l1 Preparation of methacryloxyisopropyl 2- (sulfomethyl)-pentanoate(a) 178 g. of 4n-propyl-1,2-oxathiolane-5-one 2,2- dioxide andB-hydroxypropyl methacrylate are reacted in toluene as described inprocedure (7)(a) above to produce methacryloxyisopropyl 2- (sulfomethyl-pentanoate.

(b) Preparation of 4-n-propyl-1,2-oxathiolane-5-one- 2,2-dioxide: 114 g.of u-methylene-pentanoic acid is re- 13 acted with sodium hydroxide toneutralize the carboxyl group. Sodium bisulfite (1 mol) solution isadded and the reaction carried out as described in procedure ()(b) toobtain 4-n-propyl-1,2-oxathiolane-5-one-2,2-dioxide of an equivalentweight of 93.

By procedure (7)(a) above, fi-hydroxyethyl methacrylate is esterifiedwith an equimolar amount of allylsulfo-succinic anhydride obtained bythe sulfonation of allylsuccinic acid anhydride obtained from propeneand maleic anhydride by a procedure analogous to that of (8) (b)hereinabove.

(13) Preparation of methacryloxyethyl 2-methyl-3-sulfo-butyrate Byprocedure (9)(a) above, S-hydroxyethyl methacrylate is reacted with anequimolar amount of 3,4- dimethyl-1,2-oxathiolane-5-one-2,2-dioxide.There is obtained a 70% yield of methacryloxyethyl 2-methyl-3-sulfo-butyrate.

The thiolane used is obtained as follows:

100 g. of a-methyl-crotonic acid is reacted with sodium hydroxide toneutralize the carboxyl group. Sodium bisulfite (104 g.) in aqueoussolution is added and the reaction continued as described in earlierexamples to obtain 3,4-dimethyl-1,2-oxathiolane-5-one-2,2-dioxide.

The reaction of this product with hydroxymethyl acrylate andmethacrylate is as described in earlier examples to give e.g.methacryloxyisopropyl a methyl-B-sulfobutanoate.

(14) Corresponding acryloxyalkyl sulfo-containing monomers Each of thepreceding procedures in Which a methacryloxy-containing compound of thepresent invention is produced is repeated with the replacement of thehydroxyalkyl methacrylate by the corresponding molar amount of ahydroxyalkyl acrylate, thereby producing the correspondingacryloxy-containing monomer.

For example, acryloxyisopropyl acid sulfophthalate is produced by mixing239 grams of 4-sulfophthalic anhydride (1.05 M), 136 grams of2-hydroxypropyl acrylate (1.05 M), 260 g. methyl methacrylate (assolvent) and 0.25 gram of monomethyl ether of hyroquinone in a reactorwhich is continuously stirred and sparged with dry air. After 2 hours at60 C. the product is cooled to room temperature and contains about 50%by weight of acryloxyisopropyl acid sulfophthalate.

This monomer can be isolated from the methyl methacrylate byprecipitating out a salt and then by filtration. The monomer salt isthen polymerized and used as a sus pending agent in the same suspensionpolymerization procedure as is disclosed in (1) (b). Furthermore, thefiltered and washed monomer salt is converted to the monomer acid byslurrying the salt in ethyl acetate and stirring with a sulfonatedstyrene/divinyl benzene ion exchange resin in acid form. The acidmonomer is then obtained in solution by filtration and polymerized bythe addition of 1% benzoyl peroxide. It is useful for the sizing ofcotton and rayon yarns which, after fabrication, can be treated With anaqueous alkaline solution to remove the size therefrom.

(15) Preparation of acryloxyethyl acid sulfophthalate Hydroxyethylacrylate (130 g.), 4-sulfophthalic anhydried (227 g.), butylacetate (250g.) and monoethylether of hydroquionne (0.25 g.) are mixed, stirred,sparged with dry air and heated at 105 C. for 3 hours and cooled.

14 (C) PREPARATION AND USE OF POLYMERS (1) 400 parts of methylmethacrylate and 1 part of azodiisobutyronitrile are added in the courseof one hour to a glass reaction vessel containing 287.5 parts of toluenemaintained at C. by means of external heating. The mixture in the flaskis stirred during the addition and subsequent reaction and maintained at8085 C. under a nitrogen atmosphere. The mixture is then diluted with332.5 parts of toluene over one hour while stirring and maintaining thetemperature at 8082 C. At the end of two hours (about conversion), asecond stage comprised of 95.0 parts of methyl methacrylate and 5.0parts of methacryloxyisopropyl acid sulfophthalate, 0.25 part ofazodiisobutyronitrile, and 25 parts of 2-methoxyethanol is added in thecourse of one hour to the same reaction vessel using the heated methylmethacrylate resin solution as the reaction medium. .Stirring andheating are continued and a reaction temperature of 80-82 C. maintained.After 5 hours the mixture is again diluted with an additional 25 partsof toluene over a one-hour period. Four, six and eight hours afterinitial polymerization has started the overall reaction is recatalyzedwith 0.1 part of additional azodiisobutyronitrile. Heating and stirringare continued for a total of 12 hours and the mixture diluted withtoluene to 30% solids. (approx. 418.3 parts of toluene). The finalGardner-Holdt viscosity is Q. The final product, a clear viscous liquid,contains a copolymer of 99 parts of methyl methacrylate and 1.0 part ofmethacryloxyisopropyl acid sulfophthalate.

Coatings are made on panels of metal primed with an acrylicpolymer/melamine formaldehyde primer. Adhesion to such panels isexcellent; coatings of poly(methyl methacrylate) lack such adhesion.Similar copolymers containing 2% of the methacryloxyisopropyl acidsulfophthalate show even stronger adhesion to various substratesincluding conventional metal primer coatings such as those based onalkyds, epoxide resins, aminoplasts, and mixtures thereof.

(2) (a) The procedure described in (C) (1) is repeated substituting forthe initial monomer charge 278.8 parts of methyl methacrylate, 119.6parts of ethyl acrylate and 1.6 parts of methacrylic acid, and alsosubstituting for the second charge 264.8 parts of methyl methacrylate,113.6 parts of ethyl acrylate, 2.0 parts of methacryloxyisopropyl acidsulfophthalate and 1.6 parts of methacrylic acid, 1.0 part ofazodisobutyronitrile, and 100 parts of Z-methoxyethanol. The resultingcomposition, when diluted to 40% solids with toluene, is a clear polymersolution having a viscosity of Z-5.

(b) Part (a) hereof is repeated using 2.0 parts of acryloxyisopropylacid sulfophthalate instead of the corresponding methacryloxy compound.

The clear solutions of parts (a) and (b) hereof are applied to varioussubstrates and dried. The coatings have good gloss, clarity and adhesionon on panels of various metals.

(3) The procedure described in (C)(2) is repeated substitutingmethacryloxyisopropyl sulfobenzoate for methacryloxyisopropyl acidsulfophthalate. The final polymer solution at 40% resin solids has aviscosity of Z.

(4) 76.25 parts of methacryloxyisopropyl acid sulfophthalate and 1 partof azodiisobutyronitrile dissolved in 48.75 parts of n-butyl acetate aremaintained at C. by means of external heating. The mixture is stirredfor 5 hours and the reaction kept under a nitrogen atomsphere. The final60% solids polymer solution has a viscosity of 500 cps.

(5) A mixture comprising 39.25 parts of methyl methacrylate, 45.1 partsof butyl acrylate, 3.3 parts of methacryloxyisopropyl acidsulfophthalate, 7 parts of methyl Cellosolve, 4.35 parts of toluene, and0.09 part of benzoyl peroxide is diluted in a glass reaction vessel with186.3 parts of toluene. The reaction flask is maintained under anatmosphere of nitrogen and external heating applied to raise thetemperature to 110 C. At reflux a mixture comprising 117.75 parts ofmethyl methacrylate, 135.3 parts of butyl acrylate, 9.9 parts ofmethacryloxyisopropyl acid sulfophthalate, 21 parts of methylCellosolve, 13 parts of toluene, and 0.27 part of benzoyl peroxide isadded over a period of two hours maintaining reflux by external heatingand maintaining the nitrogen atmosphere in the reaction flask. Afterthis addition, reinitiation is effected by a one-hour addition of 1.58parts of benzoyl peroxide dissolved in 118.3 parts of toluene. At 25 C.the resulting light brown polymer solution has a viscosity of 4970 cps.at 48.8% resin solids.

(6) (a) A polymer similar to that described in (C)() is prepared withmethacryloxyisopropyl sulfopropionate substituted formethacryloxyisopropyl acid sulfophthalate. The product has a viscosityof 4000 cps. at 50% polymer solids.-

(b) A polymer similar to that described in (C)(5) is prepared withmethaeryloxyethyl acid sulfophthalate substituted formethacryloxyisopropyl acid sulfophthalate. The product has a viscosityof 4000 cps. at 50% polymer solids.

The polymer solutions of (C)(3), (4), (5) and (6)(b) are used forcoating various substrates, especially metals primed with variouscommercial primers. The solutions may be so applied to provide clearprotective coats on drying or they may be formulated with pigments, suchas TiO before application. For example, a solution of a respective oneof the polymers is diluted to about 15% polymer solids and 100 parts ofthis diluted solution is mixed with about 12 parts of T in a suitablemill. The clear, as well as the TiO -pigmented lacquers, exhibitviscosity stability over a reasonably long storage time, such as isevidenced by an accelerated storage test over a period of 72 hours at140 F.

(7 A mixture of 24 parts of a 28% aqueous solution of sodiumoetylphenoxydiethyoxyethyl sulfonate in 376 parts of water is placed ina vessel equipped with stirrer, condenser, gas inlet, and thermometer.After purging with nitrogen, the following ingredients are added: 15.6parts of a 55% solution methacryloxyisopropyl acid sulfophthalate inmethyl methacrylate, 100 parts of butyl acrylate, 85.2 parts of methylrnethacrylate, 20 parts of a 0.15% aqueous solution of ferrous sulfateheptahydrate, and a solution of 1 part of ammonium persul-fate in 5parts of water. After stirring for minutes, the batch is cooled to 25 C.and a solution of 0.7 part of sodium formaldehyde sulfoxylate in 5 partsof Water is added followed by 0.12 part of 70% t-butyl hydroperoxide.Polymerization begins immediately, and the temperature rises to 66 C. in7 minutes. The batch is held at 66 C. for 15 minutes, cooled andfiltered through cheese cloth. A negligible quantity of gum is formed; astable latex is obtained with a solids content of 32.1% and a pH of 1.7.

(8) Procedure (C) (7) is repeated except that the methacryloxyisopropylacid sulfophthalate is replaced by the corresponding amount of each ofthe following monomers:

(a) acryloxyethyl acid sulfophthalate (b) methacryloxyisopropylsulfobenzoate (c) methacryloxyethyl sulfobenzoate (9) There are mixedand ground on a roller mill 266.2 parts of titanium dioxide, 76.0 partsof lithopone, 51.5 parts of mica, 80.7 parts of silica, 6.8 parts of theformaldehyde-condensed sodium naphthalene sulfonate, 7.2. parts ofdiethylene glycol, and 189.5 parts of Water. When this mixture has beenground to a smooth, uniform paste, it is mixed with 258 parts of adispersion of interpolymer, which contains 32% solids and which has beenprepared as in (C) (7) above. When the parts used are pounds, thisformula yields 100 gallons of a white fiat paint. It weighs 11.96 poundsper gallon, contains 59.6% of non-volatile l 6 matter, has a pigment tobinder ratio of 2:1, and has a pigment volume concentration of 36% Theresulting water-base paint provides coatings on a wide variety ofsubstrates, such as masonry, plaster, wood, metals, and various plasticmaterials which coatings show good to excellent adhesion to most if notall, such as steel, galvanized iron, aluminum and copper, of thesesurfaces under normal conditions of use.

(10) Each of the polymer dispersions of (C)(8)(a), (b), and (c) areformulated into Water-base paints in the same way as described in (9)immediately above. Coatings have similar qualities of adhesion anddurability as those obtained from the paint made in (9) above.

(11) Procedure (C) (1) is repeated with similar results substituting forthe methacryloxyisopropyl acid sulfophthalate each of the followingmonomers respectively:

(a) methacryloxyethyl acid sulfo-(n-propyl)-succinate (b)methacryloxyethyl acid sulfo-(methyD-succinate (c) methacryloxyethylacid sulfo-(n-bu-tyl)-succinate (d) methacryloxyethylsulfo-(2,3-dimethyl)-propionate (e) methacryloxyisopropylfi-sulfohexanoate (f) methacryloxyisopropyl 2-(sulfomethyl)-pentanoateWe claim: 1. A compound selected from the group consisting of (1) acompound of the formula where R is selected irom the group consisting ofhydrogen and methyl,

A is an alkylene group having 2 to 10 carbon atoms, at

least 2 of which extend in a chain between the adjoined oxygen atoms,and

X is a benzene ring substituted by at least one sulfonic acid group, and(2) salts thereof selected from the group consisting of alkali metal,alkaline earth metal, ammonium, lower alkyl primary, secondary, andtertiary amines, mono-, di-, and triethanolarnine, andbenzyltrimethylammonium salts.

2. A compound selected from the group consisting of (1) the product ofthe reaction of an anhydride of phthalic acid containing at least onesulfonic acid group with a compound of the formula wherein R is selectedfrom the group consisting of hydrogen and methyl and A is an alkylenegroup having 2 to 10 carbon atoms, at least 2 of which extend in a chainbetween the adjoined oxygen atoms, the molar ratio of hydroxyester toanhydride being from 1.5:1 to 1:2, and (2) salts thereof selected fromthe group consisting of alkali metal, alkaline earth metal, ammonium,lower alkyl primary, secondary, and tertiary amines, mono-, di-, andtriethanolamine, and benzyltrimethylammonium salts.

3. The product of reaction of a mixture of Z-hydroxypropyl methacrylateand 4-sulfophthalic anhydride, the molar ratio of hydroxyester toanhydride in the mixture being 1:1.

4. The product of reaction of a mixture of hydroxyethyl acrylate and4-sulfophthalic anhydride, the molar 18 ratio of hydroxyester toanhydride in the mixture being References Cited 1:1. Brewster et 211.,Organic Chemistry, Prentice Hall Inc.,

5. The product of reaction of a mixture of Z-hydroxy- (1961) propylacrylate and 4-sulfophtha1ic anhydride, the molar 5 LORRAINE H.WEINBERGER, Primary Examiner ratio of hydroxyester to anhydride in themixture being J, F, TERAPANE, A sistant ExaminerMethacrybxyiwpmpyl'sulfbenzate' 117 72, 75, 132, 161; 260-79.3 MU, 327s, 346.3, 7. Methacryloxyethyl o-sulfobenzoate. 10 346.8, 353, 355, 481

